I did not think that there were Maxim's at Cuba. But I could be wrong. The book "The Gatlings at Santiago" gives a great accounting of the Gatling guns. Though I did not think they had converted them to .30 Army (Krag). I thought they were still .45/70. But the picture is of Gatlings in the Philippines, where it is possible that small cal. Gatlings were used. Gatlings were still being used in training units... in1914. They did not go away until WW1.
The gun that most seems to be missing is the Single Action Army. The Roughriders took a delivery of some 500 guns before shipping out. I 'think' they may have been ordered through Abercrombie and Fitch. Guns from that lot still show up occasionally and when Colt Issues you a letter... they charge a crapload of extra money because their letter verifies your gun as being worth... a fortune.
Other than that... what's missing? Were some of the early Mausers in use by the Spanish? Smokeless powder and all?
I have not opened my paper copy yet. I'll read in more detail in the 'Eljer library.'
Cheers,
Sirhr